A surface protective layer and an interlayer insulating film for a semiconductor device can use a polyimide resin having excellent heat resistance, electrical characteristics, mechanical characteristics, and the like. The polyimide resin has recently been used as a photosensitive polyimide precursor composition. The photosensitive polyimide precursor composition can be easily coated on a semiconductor device, patterned by ultraviolet (UV) rays, developed, and thermally imidized, to form a surface protective layer, an interlayer insulating film, and the like. Accordingly, the photosensitive polyimide precursor composition may remarkably shorten processing times as compared with a conventional non-photosensitive polyimide precursor composition.
However, the positive photosensitive polyimide precursor composition may not provide the desired pattern, because the carboxylic acid of the polyamic acid is too highly soluble in an alkali. In order to solve this problem, a material having a phenolic hydroxy group instead of carboxylic acid has been suggested (Japanese Patent Laid-open Pyong 10-307393). This material, however, can be insufficiently developed and can cause film loss or result in resin delamination from a substrate.
Recently, another material prepared by mixing the polybenzoxazole precursor with a diazonaphthoquinone compound has drawn attention (Japanese Patent Laid-open Sho 63-96162). However, when actually used as the polybenzoxazole precursor composition, film loss of an unexposed part can be remarkably increased, so that the desirable pattern cannot be obtained after development.
In addition, there is a need for research on a dissolution-controlling agent, since a phenolic compound used to adjust solubility decomposes at a high temperature during thermal curing, causes a side reaction, or the like and, which can result in decreased mechanical properties of a cured film.